Singapore has so far been spared a second wave of coronavirus infections, although the number of community cases has increased after the end of circuit breaker measures, said Health Minister Gan Kim Yong.

However, risks remain, he told a virtual press conference yesterday.

It has been more than a month since circuit breaker ended and while there are no plans to impose additional restrictions or put in place another nationwide circuit breaker, they cannot be ruled out, said National Development Minister Lawrence Wong.

"Countries that exited from their lockdowns have had to reimpose lockdowns. But we will try very hard not to have to go down that path," said Mr Wong.

An expanded toolkit of control measures, built up over the past few months, is key in preventing this, said Mr Wong who, together with Mr Gan, helms the Covid-19 task force.

The measures include casting a wider net around virus cases, testing more extensively and putting more contacts on quarantine, Mr Wong added.

"We might even have to do a localised restriction measure for that particular area if there's a cluster in that area," he said.

"Hopefully with all of these measures, we can control the infection effectively without having to impose another nationwide circuit breaker."

At the press conference, Associate Professor Kenneth Mak, director of medical services at the Ministry of Health, referred to social media talk that restrictions were going to be reinstated after the election.

He said: "We continue to keep a close watch on the community (cases) but we don't have plans to say that immediately after elections, we're going to quickly go back into phase one.

"That's not the case."

Stressing the need for everyone to be vigilant, Mr Gan cited the nine people living in Block 111 Tampines Street 11 with Covid-19.

The cases come from two households on different floors, but they share the same lifts and stairwell.

Mr Gan said: "To be honest, when we saw the cluster in Tampines St 11, I was very concerned that this could be a major outbreak for us because we have quite a number of cases within one household, and then it had some connection to the second household."

This is why there was a need to "move aggressively and do more than what is usually the standard practice" by testing everyone in the section of the block.

A total of 118 people who live in or visited the clusters at the block have been tested for Covid-19 since the end of last month.

All have tested negative.

"We have not been able to establish conclusively what's the connection between the two (households), but there is a suspicion that there would have been some connection between the two clusters," pointed out Mr Gan.

"And there is also a risk that you could have a third cluster popping up from the Tampines group of households and we could have a spread to other settings beyond just the households arising from this group."

Investigations are ongoing to narrow it down to a particular link or cause.

In the meantime, those living in the same section of the block that share a common lift lobby and stairwell have been placed on active phone surveillance.

"Once we see a possible cluster forming, we will move in quickly to impose precautionary measures to break the chain of transmission," stressed Mr Gan.

He urged residents to abide by the safe management rules and maintain good hygiene habits to prevent a second wave of infections.

"We must continue to remain vigilant. Because if we let our guard down, the virus will creep in and the infections will grow."